Merge pull request #2568 from Textualize/empty-paste

Fix empty paste

CHANGELOG.md

@@ -20,6 +20,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Fixed `TreeNode.collapse` and `TreeNode.collapse_all` not posting a `Tree.NodeCollapsed` message https://github.com/Textualize/textual/issues/2535
 - Fixed `TreeNode.toggle` and `TreeNode.toggle_all` not posting a `Tree.NodeExpanded` or `Tree.NodeCollapsed` message https://github.com/Textualize/textual/issues/2535
 - `footer--description` component class was being ignored https://github.com/Textualize/textual/issues/2544
+- Pasting empty selection in `Input` would raise an exception https://github.com/Textualize/textual/issues/2563
 
 ### Added
 

src/textual/widgets/_input.py

@@ -332,8 +332,9 @@ class Input(Widget, can_focus=True):
             event.prevent_default()
 
     def _on_paste(self, event: events.Paste) -> None:
-        line = event.text.splitlines()[0]
-        self.insert_text_at_cursor(line)
+        if event.text:
+            line = event.text.splitlines()[0]
+            self.insert_text_at_cursor(line)
         event.stop()
 
     async def _on_click(self, event: events.Click) -> None:

tests/test_paste.py

@@ -1,5 +1,6 @@
 from textual import events
 from textual.app import App
+from textual.widgets import Input
 
 
 async def test_paste_app():
@@ -16,3 +17,28 @@ async def test_paste_app():
 
     assert len(paste_events) == 1
     assert paste_events[0].text == "Hello"
+
+
+async def test_empty_paste():
+    """Regression test for https://github.com/Textualize/textual/issues/2563."""
+
+    paste_events = []
+
+    class MyInput(Input):
+        def on_paste(self, event):
+            super()._on_paste(event)
+            paste_events.append(event)
+
+    class PasteApp(App):
+        def compose(self):
+            yield MyInput()
+
+        def key_p(self):
+            self.query_one(MyInput).post_message(events.Paste(""))
+
+    app = PasteApp()
+    async with app.run_test() as pilot:
+        await pilot.press("p")
+        assert app.query_one(MyInput).value == ""
+        assert len(paste_events) == 1
+        assert paste_events[0].text == ""